Signal Missing
Signal missing
Checking the function
Checking the rain sensor
Checking the function
- Ignition on
- Activate the rain sensor.
Hint: The wiper blades make a reference stroke to determine the cleanliness and condition of the windshield when the rain sensor is activated. The rain sensor is deactivated when the ignition is switched off. To reactivate the rain sensor with the ignition on, move the stalk to position "0" and then to intermittent wiping.
Spray water on the windshield where the rain sensor is positioned.
The wiper blades must now wipe the windshield clean.
Hint: In cars equipped with the rain sensor it replaces the intermittent function. One way of checking the function of the rain sensor is to twist the collar on the lever. This changes the sensitivity of the rain sensor. The windshield wiper should make one stroke. If the intermittent or high speed functions are activated it indicates that the rain sensor function is missing.
Continue - ANOTHER TEST
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ANOTHER TEST - Checking the supply to the rain sensor
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Checking the supply to the rain sensor
- A number of measurements are required to check the wiring for the rain sensor. Measurements should be carried out on the wiring connector with the rain sensor disconnected. The terminals correspond to ground, voltage and data cables. The data cable is connected to terminal #1 on the rain sensor, terminal #2 is the ground cable and terminal #3 is the power supply for the rain sensor
- Move the windshield wiper stalk to position "0".
- Ignition off
- Disconnect the rain sensor
- Ignition on.
Check the voltage level between the voltage terminal #3 and ground terminal #2 of the wiring.
Hint: The voltage must be 12V.
Other information:
- For further information about signals and other values, see Signal specification Signal Specification, Upper Electronic Module (UEM)
- Rain sensor Service and Repair
- Checking wiring and terminals Checking Wiring And Terminals.
Is the voltage between the terminals 12V?
Yes - Checking the data cable
No - Checking the wiring
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Verification
Verification
Verification
Note! After carrying out the repair, check that the fault has been remedied.
- Ignition off
- Reinstall the connectors, components etc.
- Ignition on
- Activate the rain sensor.
Hint: The wiper blades make a reference stroke to determine the cleanliness and condition of the windshield when the rain sensor is activated. The rain sensor is deactivated when the ignition is switched off. To reactivate the rain sensor with the ignition on, move the lever to position 0 and then to intermittent wiping.
Spray water on the windshield where the rain sensor is positioned.
The wiper blades must now wipe the windshield clean.
Is the rain sensor functioning?
Yes - VERIFIED
No - VERIFICATION FAILED
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VERIFIED - Fault Found
VERIFICATION FAILED - Fault-tracing information
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Fault-tracing information
Information
Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.
Do you want to exit fault-tracing?
Yes - FAULT-TRACING FAILED
No - Attempt New Test
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Attempt New Test - Checking the function
FAULT-TRACING FAILED - No Fault Found
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Checking the data cable
Hint: The wiring between upper electronic module (UEM) and the rain sensor consists of two cables.
The upper electronic module (UEM) transmits pulses to the rain sensor using the data cable.
Disconnect the rain sensor.
Check that the data is transmitted on the data cable terminal #1 by checking the voltage level between the data and ground cables for the wiring (that is terminals #1 and #2).
Hint: Use the oscilloscope function and check that a pulsed signal is transmitted. The difference between the high and low values of the pulses is approximately 12 V. In the event of an open-circuit in the data cable no pulses are transmitted and a continuous voltage is displayed.
If the difference between high and low values of the pulses is between 2 V and 10 V it indicates that the wiring is oxidized or trapped. Replace the wiring between the rain sensor and the roof wiring in the event of a fault.
If no other fault is found try replacing the rain sensor.
Remedy as necessary.
Other information:
- To access or replace the control module, see Upper electronic module (UEM) rear view / door mirror, replacing Service and Repair
- Rain sensor Service and Repair
- For further information about signals and other values, see Signal specification Signal Specification, Upper Electronic Module (UEM)
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box
- Checking wiring and terminals Checking Wiring And Terminals.
Continue - Verification
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Checking the wiring
There is either a fault in the supply voltage or in the ground lead. Check the power supply cable against a ground terminal (the chassis).
Hint: If the voltage is 12 V the fault is in the ground lead. Other wise the fault is in the power supply cable.
Remedy as necessary.
Other information:
- To access or replace the control module, see Upper electronic module (UEM) rear view / door mirror, replacing Service and Repair
- Rain sensor Service and Repair
- For further information about signals and other values, see Signal specification Signal Specification, Upper Electronic Module (UEM)
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box
- To fault-trace the wiring and terminals, see Checking wiring and terminals Checking Wiring And Terminals.
Select "Continue".
Continue - Verification
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